Laminated magnetic structure, and process for making same



Oct. 9, 1962 w. A. RAY 3,058,039

LAMINATED MAGNETIC STRUCTURE, AND PROCESS FOR MAKING SAME Filed June 24. 1957 A .12 J2 2Z 2 mun/w A. 124% INVENTOR.

BY QMM 1% United States Patent Office 3,058,939 LAMINATED MAGNETEC STRUCTURE, AND PROCESS FDR MAKING SAME William A. Ray, North Hollywood, Caiih, assignor to General Controls (10., a corporation of California Filed June 24-, 1957, Ser. No. 667,463 1 Claim. (Cl. *17-198) This invention relates to magnetic laminated structures.

Magnetic cores for electromagnets and relays, and adapted to be operated by alternating current, are almost universally made up of laminations. In many of these devices, there is a movable armature attracted by the core for the electromagnet coil. It is essential that the contacting surfaces of the core and armature be as perfectly plane as possible, so as to cause the contact between these elements to be as close as possible, and thereby improve the operation of the relay or magnet.

Since usually the laminations are held together by fastening means, such as rivets passing through clearance holes in the laminations, it is not to be expected that the resultant surfaces formed by the edges of the laminations would all lie in the same plane. This is obvious because of the looseness of the fit of the rivets in the clearance holes. Accordingly, it is common to grind ofi these edges to form a geometrically true plane surface.

It is one of the objects of this invention to obviate these expensive operations, and yet to make it possible to produce substantially true plane surfaces intended to be placed in contact with other elements of the magnetic circuit.

In some instances, the core for the magnet coil is formed as an E, the ends of the arms being adapted to attract an armature extending across the faces of these arms. Often the center arm is purposely made shorter than the outer ones, whereby a small air gap is formed between it and the armature. The amount of cutback is fairly critical, and variations from the desired air gap value result in unsatisfactory magnetic operation, usually with a tendency to hum.

it is accordingly another object of this invention to provide substantially accurately defined air gaps in cores of this character.

In order to accomplish these results, the present invention contemplates a Welding operation to hold the laminations in accurate alignment before the rivets are applied. Thus haphazard variations in the stacking of the laminations prior to riveting are prevented.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose, there is shown a form in the drawings accompanying and forming a part of the present specification. This form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claim.

Referring to the drawings:

FIGURE 1 is an elevation showing two stacks of laminations which are designed to incorporate the core invention;

'FIG. 2 is a side view thereof;

FIG. 3 is a view similar to FIG. 1, but illustrating the stacks joined together by a welding operation;

FIG. 4 is a side view of the stacks illustrated in FIG. 3; and

FIG. 5 is a fragmentary pictorial view illustrating one of the welded ridges of the stack of laminations.

The laminations 1 are shown in this instance as E-shaped, having outer arms 2 and 3, a central arm 4 and a base member 5. The space between each of the outer arms 2 and 3 and the center arm 4 is arranged to accommodate a winding.

The stack of laminations 6 constitutes an armature structure adapted to be attracted by the stack 1.

In the present instance, the outer edges 16 of the arms 3 and 4 are adapted to lie on a plane 9, and to contact with the lower edge 17 of the stack 6. The upper edge 13 of central arm 4 is disposed slightly below these outer edges so as to provide a relatively small gap between arm 4 and stack 6. Furthermore, each of the arms 2 and 3 is provided with a slot 7 and 8 for accommodating a shading coil. The inside projections 19 of arms 2 and 3 are also shown cut back slightly below the plane 9.

The plane 9 is intended to be parallel to and cooperate with plane 10 corresponding to the cooperating face of the stack of laminations 6.

Each of the laminations comprising stack :1 is also provided with one or more cars ll at a place remote from the edges of the arms 2 and 3. The laminations 6 are also each provided with corresponding ears 12 on that side of the laminations remote from plane 10.

In preparing the stack of laminations, the upper edges 16 are placed against a geometrically perfect plane 9; and one of arms 2 or 3 of each lamination is placed along a corresponding plane 13 perpendicular to plane 9. They are temporarily held in this position in any appropriate manner. Then the ears Ill are welded together. This welding can be effected by the heliarc or inert gas welding without the necessity of adding material. At the completion of the welding operation, a continuous ridge 14 (FIGS. 3, 4 and 5) of welded metal is formed transverse of the stack of laminations. This Welding is accomplished, of course, while the stack is held against the surfaces 9 and 13.

At the completion of the welding operation, the stack may be permanently joined as by the aid of fastening means 15, such as rivets, passing through appropriate apertures 26 in the laminations.

By placing the ears Jill and 12 at the outer edges of the laminations, the welded parts are kept substantially entirely out of the flux path.

The armature laminations 6 are also joined together as by welding the cars 12 to form the ridges 21 (FIGS. 3 and 4). This is accomplished while the laminations 6 are held against the geometrically flat surfaces 10 and 18 which are mutually perpendicular.

Thus, the planes 9 and it) serve to align the edges of the laminations 1 and 6 to conform to a geometrically fiat surface; and these laminations are permanently joined while in that position.

The critical requirement of substantially accurate flatness of the cooperating edges of the stacks of laminations is readily obtained by this process. Accordingly, annoying humming or inefficiency in operations may be avoided without the necessity of grinding the cooperating contacting surfaces.

The inventor claims:

In an electromagnetic relay structure: a first stack of Patented Get. 9, 1962 3 identical laminations forming an electromagnet core, and each having end edges falling in a first common plane to define a polar area; means forming a unitary weld extending transversely of the first stack of laminations at a place remote from said polar area to confine the laminations against relative sliding movement, thereby causing said end edges to remain in said first common plane; clamping means extending transversely through the first stack of laminations, preventing separating movement of the first stack of laminations; a second stack of identical laminations forming an .electromagnet armature, and each having edges falling in a second common plane to define an area for cooperation with said polar area; means forming a unitary Weld extending transversely of the second stack of laminations at a place remote from its said area to confine the laminations against relative sliding movement, thereby causing the end edges to remain in said second common plane; and clamping means extending transversely through the second stack of laminations,

preventing separating movement of the second stack of laminations.

References Cited in the file of this patent UNITED STATES PATENTS 577,480 Gutmann Feb. 23, 1897 1,696,615 Trombetta Dec. 25, 1928 2,207,572 Ayers July 9, 1940 2,330,824 Gr-anfield Oct. 5, 1943 2,447,911 Mages et a1. Aug. 24, 1948 2,488,961 Camilli Nov. 22, 1949 2,538,036 Ponstingl Jan. 16, 1951 2,762,988 Pornazal et a1 Sept. 11, 1956 OTHER REFERENCES Holland: Abstract of Application Serial No. 755,368, published January 17, 1950, 630 0.6. 859. 

